1. Field
The present disclosure pertains to the field of processing systems, and particularly the use of a secondary processing resource to execute instructions under some conditions.
2. Description of Related Art
Several techniques are presently used to control temperature and power consumption of electronic components such as processors. Typically, maintaining a temperature of a component at an acceptable level is important to avoid damaging the component as well as to ensure safety. On e way to control or reduce temperature is to limit power consumption. Additionally, with the popularity of mobile computing and communications devices, limiting power consumption to preserve battery life is an increasingly important goal as well. Thus, power conservation may be advantageous to limit heat generation, to preserve battery power, or both.
Dynamic clock disabling is one prior art technique to reduce power consumption. Dynamic clock disabling is the temporary or intermittent stopping of the clock or clocks of a processor. During the period in which the clock is stopped, clearly less power is consumed; however, no work can be performed if all of the clocks are stopped. In some cases, a reduced level of functionality may be provided by periodically stopping clocks; however, during “on” periods large and power-hungry high performance logic structures are used. Another variation is to recognize when there is no work to be done, and to stop the clocks at that point in time. Another variation is to stop clocks to a particular functional unit (e.g., a floating point unit) when that unit is idle. However, when a unit or processor is idled, no work is accomplished.
Dynamic frequency scaling is the change of processing frequency, typically effectuated by altering a clock frequency of the processor. While reduction of operating frequency decreases power proportionately, dynamic frequency scaling may in some cases require that a phase locked loop re-acquire lock, which can be a relatively time consuming proposition. Moreover, dynamic frequency scaling also still keeps large power-hungry structures active.